 /*******************************************************************************
  * Copyright (c) 2006, 2007 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
  * IBM Corporation - initial API and implementation
  *******************************************************************************/
 package org.eclipse.ui.texteditor.spelling;

 import java.util.ArrayList ;
 import java.util.Arrays ;
 import java.util.Iterator ;
 import java.util.List ;

 import org.eclipse.jface.text.Position;
 import org.eclipse.jface.text.contentassist.ICompletionProposal;
 import org.eclipse.jface.text.quickassist.IQuickAssistInvocationContext;
 import org.eclipse.jface.text.quickassist.IQuickAssistProcessor;
 import org.eclipse.jface.text.source.Annotation;
 import org.eclipse.jface.text.source.IAnnotationModel;
 import org.eclipse.jface.text.source.ISourceViewer;
 import org.eclipse.jface.text.source.TextInvocationContext;

 import org.eclipse.ui.internal.texteditor.spelling.NoCompletionsProposal;


 /**
  * Spelling correction processor used to show quick
  * fixes for spelling problems.
  *
  * @since 3.3
  */
 public final class SpellingCorrectionProcessor implements IQuickAssistProcessor {
     

     private static final ICompletionProposal[] fgNoSuggestionsProposal= new ICompletionProposal[] { new NoCompletionsProposal() };
     

     /*
      * @see IContentAssistProcessor#computeCompletionProposals(ITextViewer, int)
      */
     public ICompletionProposal[] computeQuickAssistProposals(IQuickAssistInvocationContext quickAssistContext) {
         ISourceViewer viewer= quickAssistContext.getSourceViewer();
         int documentOffset= quickAssistContext.getOffset();

         int length= viewer != null ? viewer.getSelectedRange().y : 0;
         TextInvocationContext context= new TextInvocationContext(viewer, documentOffset, length);


         IAnnotationModel model= viewer.getAnnotationModel();
         if (model == null)
             return fgNoSuggestionsProposal;

         List proposals= computeProposals(context, model);
         if (proposals.isEmpty())
             return fgNoSuggestionsProposal;

         return (ICompletionProposal[]) proposals.toArray(new ICompletionProposal[proposals.size()]);
     }

     private boolean isAtPosition(int offset, Position pos) {
         return (pos != null) && (offset >= pos.getOffset() && offset <= (pos.getOffset() + pos.getLength()));
     }

     private List computeProposals(IQuickAssistInvocationContext context, IAnnotationModel model) {
         int offset= context.getOffset();
         ArrayList annotationList= new ArrayList ();
         Iterator iter= model.getAnnotationIterator();
         while (iter.hasNext()) {
             Annotation annotation= (Annotation)iter.next();
             if (canFix(annotation)) {
                 Position pos= model.getPosition(annotation);
                 if (isAtPosition(offset, pos)) {
                     collectSpellingProblems(annotation, pos, annotationList);
                 }
             }
         }
         SpellingProblem[] spellingProblems= (SpellingProblem[]) annotationList.toArray(new SpellingProblem[annotationList.size()]);
         return computeProposals(context, spellingProblems);
     }

     private void collectSpellingProblems(Annotation annotation, Position pos, List problems) {
         if (annotation instanceof SpellingAnnotation)
             problems.add(((SpellingAnnotation)annotation).getSpellingProblem());
     }

     private List computeProposals(IQuickAssistInvocationContext context, SpellingProblem[] spellingProblems) {
         List proposals= new ArrayList ();
         for (int i= 0; i < spellingProblems.length; i++)
             proposals.addAll(Arrays.asList(spellingProblems[i].getProposals()));
         
         return proposals;
     }

     /*
      * @see IContentAssistProcessor#getErrorMessage()
      */
     public String getErrorMessage() {
         return null;
     }

     /*
      * @see org.eclipse.jface.text.quickassist.IQuickAssistProcessor#canFix(org.eclipse.jface.text.source.Annotation)
      */
     public boolean canFix(Annotation annotation) {
         return annotation instanceof SpellingAnnotation && !annotation.isMarkedDeleted();
     }

     /*
      * @see org.eclipse.jface.text.quickassist.IQuickAssistProcessor#canAssist(org.eclipse.jface.text.quickassist.IQuickAssistInvocationContext)
      */
     public boolean canAssist(IQuickAssistInvocationContext invocationContext) {
         return false;
     }

 }

